[The prevalence of dementia in old age]

The risk of manifestation of dementia increases as the population grows older. The prevalence of dementia increases from 0.7% in age group 60-64 years to 38.8% in age group 90-94 years. Over 60, the prevalence rate doubles every 5.1 years. The most common types of dementia are Alzheimer's dementia and vascular dementia.